- fixed indentation (2 spaces)

- added missing new lines at the end of files
- removed 'ps-theme-big-and-ugly' theme
- improved readme.md. Added an example on how to create custom themes with scss.

src/css/mixins.scss

@@ -1,4 +1,4 @@
-// Helper mixins TODO: get rid of these mixins: https://github.com/noraesae/perfect-scrollbar/issues/431
+// Helper mixins
 @mixin border-radius($r) {
   -webkit-border-radius: $r;
   -moz-border-radius: $r;
@@ -117,4 +117,4 @@
       }
     }
   }
-}
+}